Deep Dives

Vaccines that Can be Used Without Last-Mile Cooling

Controlled temperature chain can extend supply chains and improve immunization coverage and equity

Benin is a West African country just north of the equator, with a wet, tropical climate. More than 90 percent of the country’s roads are unpaved, and more than half of the population lives in the countryside, factors that complicate delivery of immunization services. During Benin’s two annual rainy seasons, roads can become almost impassable, making it challenging for health workers to keep vaccines cool on their longer journeys to rural communities.

Use of MenAfriVac®—approved in 2012 for use against meningitis A—was a new solution to this challenge. Like many vaccines, MenAfriVac is relatively heat stable, and can withstand exposure to ambient temperatures of 30 degrees Celsius and higher for multiple days. However, in accordance with global immunization guidelines, most manufacturers label their vaccines for storage between 2 and 8 degrees Celsius.

Recognizing the missed opportunity to label vaccines according to their true temperature stability, the World Health Organization (WHO) in 2015 began working on a new policy called the Controlled Temperature Chain. With urging from WHO and PATH, the MenAfriVac manufacturer—the Serum Institute of India—agreed to label the vaccine in accordance with its actual heat stability, allowing the vaccine to be stored for several days at higher temperatures, still without exceeding the 40 degree Celsius limit.

With this new vaccine labeling procedure, health workers can use MenAfriVac in a controlled temperature chain, or CTC. As described in “Building Next Generation Supply Chains”, CTC provides an opportunity to extend supply chains and improve immunization coverage and equity. The protocol for CTC allows health workers to transport vaccines in coolers without ice for several days as long as they use vaccine vial monitors to track the temperature inside each vial. Health workers must also track the ambient temperature—which should not exceed 40 degrees Celsius—by placing a special laminated card in each cooler that works just like a vaccine vial monitor, except that it measures peak temperatures and turns green if the temperature inside the cooler exceeds 40 degrees Celsius.

MenAfriVac was deployed in Banikoara, a district in the northern part of Benin. Banikoara is 60 kilometers from the nearest paved road, with only one small hospital and poor access to electricity, all of which make consistent refrigeration exceptionally difficult. During the dry season, it takes health workers a little more than a half hour to reach vaccination sites; during the rainy seasons it can take all day.

Because vials of MenAfriVac can be stored without refrigeration for the last few days prior to use, health workers in Banikoara can now carry more vaccines to remote parts of the district and stay for several days at a time, instead of having to return to their home facility daily to refill their coolers with ice packs to keep the vials cold.

While examining how the CTC worked in Banikoara, WHO found that the weight of a vaccine container dropped from 4 kilograms for a typical vaccine that requires ice packs, to just over 1.5  kilograms for CTC vaccines packed without ice packs. Using a controlled temperature chain improved logistics immensely as it drastically reduced the number of back-and-forth trips required, saving both staff and transportation costs.

Because of all these factors, the controlled temperature chain in Banikoara helped significantly improve immunization coverage rates. Overall, six countries have used MenAfriVac in a CTC, vaccinating 4 million individuals who would otherwise had to have been reached by the vaccine kept in cold storage.

Other vaccines being piloted for CTC use include oral polio in Chad and the human papillomavirus vaccine (HPV) in Vietnam and Uganda. The pneumococcal conjugate vaccine (PCV13) was authorized for use in a CTC in 2016, and oral cholera, hepatitis B, tetanus toxoid, and rotavirus vaccines are also under consideration. All vaccines approved for use in a CTC must be used in a campaign setting. CTC is not currently recommended for routine immunization delivery.

Vaccines labeled for CTC represent an exciting breakthrough for everyone involved in immunization efforts. By simplifying the supply chain—through removing the need for constant refrigeration—this technological breakthrough allows for health workers to shift their focus from transporting vaccines to using them for their intended purpose: to prevent disease.